Compared to Venus flytraps, which clamp their jaw-like leaves around flies and other small, wriggly bits of prey, the various pitcher plants in existence must seem like pretty benign carnivores. Their way of capturing prey strikes me as a bit like windmill fighting: can they help it if juicy insects and ripe-looking amphibians happen to tumble into the pits of digestive enzymes waiting at the bottom of their pitcher-shaped leaves?

In fact, pitcher plants don’t consume every organism that ends up in the pit. Some of those organisms actually help pitcher plants process the other creatures they’re about to eat, somewhat like parents who cut their children’s food for them, though slightly more savage.

Nepenthes is a genus of pitcher plant found primarily in the southeast Pacific. Each leaf starts with a thin tendril at the tip, then inflates like a long balloon until finally, at maturity, a flap of leaf material at the tip opens, and a pitcher is formed.

Pitchers in general are excellent for holding liquid, and those belonging to the plants of genus Nepenthes are no exception, though the sweet, attractive nectar and the digestive enzymesthat they produce differ substantially from the iced tea you might pour yourself on a hot summer day.

As effective as the digestive juices that Nepenthes make (capable, in some species, of taking out entire mice) are, the digestion process can always stand to go more quickly. Some Nepenthes have tiny hollow chambers in their stems where ants can make their homes. Instead of falling into the pitchers, the ants snag other insects attracted by the nectar. The ants are sloppy eaters, which is a good thing for Nepenthes, as the stray insect crumbs slip into the pitcher and get digested much sooner than an entire insect would.

So some ants and some pitcher plants make good matches. Others, not so much. Sarracenia is another genus of pitcher plant; some of its member species grow from the grounds of peat bogs in North America (including Illinois’ own Volo Bog). A Sarracenia‘s pitcher looks different from that of a Nepenthes, in part thanks to a flange running the length of the leaf that creates a stream of nectar. Ants climb the leaf and follow the trail, which leads to the edge of the long, tall pit, and—whoops, in they go.

That’s not to say that Sarracenia species can’t play nicely with others. The larvae of some insects, such as the blowfly, live inside the pitcher and feed on partially digested remains, while bacteria in the water that also collects in the bottom of the pitcher help get that digestion going in the first place.

Though they pose a threat to some living creatures, pitcher plants hardly are isolated organisms, at least within a habitat. In the case of Nepenthes, our evolutionary tree suggests otherwise, as Nepenthes are believed to exist much in the same form that they have for millions of years. In other words, the Nepenthes genus has no close relatives.

Some caterpillars possess amazing defense mechanisms, the kind that exist to make parents and guardians forever fretful when their kids go out to play. Other caterpillars mimic bird poop. I guess the phrase “different strokes for different folks” applies to the non-folks of the animal kingdom as well.

The photo that inspired today’s post.

Caterpillars are the larval forms of both moths and butterflies, squishy little worm-like creatures that emerge from eggs. Their squishiness makes them incredibly attractive to several members of the animal kingdom including birds and squirrels that, like me around midnight, are always on the lookout for a snack that’s easy to eat.

So to become a bit more difficult to eat, several species’ caterpillars have evolved features along their bodies that discourage other animals from poking at them, usually through the always discouraging use of toxic chemicals. The larval forms of such frequent flyers as the Io Moth, the Buck Moth, and the Hag Moth all have bodies lined with stinging hairs and quills that are connected to poison sacs. These hairs can break skin, allowing the toxic chemical to seep beneath them. Humans who get stung by these caterpillars may experience symptoms ranging from minor irritation to everybody’s favorite, intestinal discomfort.

Given how most people feel about having a churning sensation in their lower abdomens, it’s understandable that a lot of people avoid touching caterpillars just to be on the safe side. The majority of caterpillars are not stinging caterpillars, though. Unlike the stinging caterpillars listed above, others have bumps on their bodies that appear harmful but really are just for show.

One such caterpillar is the Black Swallowtail. During some of its larval stages (and larval stages are called instars, in case you were wondering, since science has names for everything), the Black Swallowtail’s body is lined with orange bumps that protrude from the surface. They look dangerous, because often in nature red and orange are used as colors that warn predators that they’re hunting something that will seriously screw them up, but Black Swallowtail caterpillars are considered by some people one of the best caterpillars for budding entomologists to try to raise.

So how do Black Swallowtail larvae stay safe? Well, they do have one protrusion that actually does mess with other animals. It’s called an osmeterium, and it’s a Y-shaped horn located at the back of the caterpillar’s head that pops out when the little squirmster is frightened and gets retracted when it once again feels safe. The osmeterium shoots a musty-smelling liquid that, while not harmful to humans, is tinged with a distinct whiff of eau du displeasure, enough to suggest that backing away is a good idea.

But before the osmeterium even comes into play, the Black Swallowtail caterpillar defends itself in another way: similar to the Tiger Swallowtail caterpillar, during its earlier instars, its body bears a splotchy white marking right in the middle. Does this white mark carry the same suggestion of poison that red body markings do? Nope. Does it make the caterpillar look like an unappetizing piece of bird poop that squirrels and other animals are likely to pass over without a second thought? It sure does!

I use witch hazel extract on my face every night. It’s derived from the leaves and barkof the common witch hazel plant, Hamamelis virginiana, and in addition to cleaning the skin is supposed to help relieve it of irritation. In light of witch hazel’s calming properties, I guess it’s a little funny that a witch hazel plant starts out, very literally, with a bang.

For a plant to produce offspring and continue that beautiful circle of life that Elton John sang about, it has to send seeds out like children into the big, bad world, a process known as seed dispersal. And just as some parents and caretakers allow their children to keep living at home after graduation, maybe staying in the basement or the pool house, while others practically pack their kids’ boxes and suitcases for them, plants go about seed dispersal in any number of ways:

The photo that inspired this post.

Letting gravity take its course

Encasing their seeds in tasty fruits for animals to eat so that the seeds will later be, um, deposited (seed dispersal plus, now with a fertilizer bonus)

Attaching lightweight structures that allow the seeds to drift serenely on the breeze

Launching them violently into the surrounding environment

That last option probably sounds made-up. It isn’t. Witch hazel seeds develop inside of a capsule that bursts at maturity. Like a circus daredevil spewed from a cannon, each seed ends up shot about twenty to thirty feet away from the parent plant. The capsule makes a popping sound upon bursting—or a bang, to go back to where we started this.

It’s nothing like the method of seed dispersal that many trees here in the Midwest employ. Wind dispersal seems more appropriate for a plant that’s used to make a soothing extract. The way that whirlybirds or helicopter seeds like the ones seen in the photo above (the technical term for a winged seed like these is a samara, presumably because “whirlybird” never stuck in scientific circles) simply flutter to the ground perhaps offers a greater sense of enchantment than the botanical equivalent of cannon fire. Plus, as mentioned before, all the other plants are doing it: various trees including ashes, the winged elm (naturally), and most conspicuously maples all produce winged seeds.

So why doesn’t the witch hazel plant give in to peer pressure? Well, as helpful as winged seeds are in spreading a plant’s offspring far and wide, that huge range of dispersal (we’re talking hundreds of feet here) comes with certain trade-offs:

Not every seed is guaranteed to land somewhere hospitable and grow, so the parent plant spends a lot of energy producing seeds that will never germinate.

In order to be light enough to dance on the spring breeze, winged seeds aren’t packed with as much nourishment as, say, the seeds packed into fruits are. As a result, some will be too poorly nourished by the time they land to sprout.

Kids like to pick them up and toss them into the air, at least where I grew up, because it looks really neat (see trade-off #1).

No doubt that witch hazel’s exploding seed pod looks (and sounds) neat, too, but the exchange there is that it takes even more energy than making a load of winged seeds to actively expel a few seeds from one’s body. Each plant evolves the method of seed dispersal best suited to its environment. If it happens to delight us with showers of whirlygigs or sudden eruptions of seed pods, well, that’s just one more way we’ve benefited from evolution, I’d say. It’s right up there with opposable thumbs in scientists’ minds, I’m sure.

[When drawing this monster, Wes said that he wanted to give it flat teeth specifically because the flat edges of incisors are specialized for chewing vegetables and plant matter. Essentially, he made the tree something of a cannibal. I think it works pretty well with the following discussion of non-animals consuming each other.]

The photo that inspired this post.

You know, of all the items in the world that can make people so giddy that they get stupid, pruning shears probably shouldn’t be on the list.

And yet I’ve seen homeowners as well as public works employees let the power that a pair of steel shears imparts lead them to some questionable choices while they pruned dead, spindly branches from trees. They approach pruning as if they were swordfighters in a martial arts epic, or people who decide to re-evaluate their phones’ contact lists after a Saturday night out drinking. Either way, they cut with a vigor that borders on hysterical joy, leaving very little when the act is done.

Pruning, however, is a delicate art. As with swordfighting and social interaction, there’s a way to do it that’s right, and several ways to do it that just leave a mess. A bad pruning cut can create a gaping hole of a wound in a tree’s wood that a certain group of parasitic organisms would love to crawl inside and infect.

First, though, before we take a trip into the nightmarish-sounding world of one living organism easing its way into another (ohmigosh, I’ve seen Alien, I know how this is going to end), let’s take a quick look at tree anatomy:

At the base of a tree branch, right where it connects to the tree trunk, is an almost turtleneck-type collar of tissue called the branch bark ridge. This ridge is the part of the tree where new wood will grow after a branch is cut away. The wood that grows back is called either wound wood, which sounds vaguely S&M-ish but isn’t, or callus tissue, which sounds like something the tree should have taken care of on a spa day.

Unlike the patches of dead skin that we loofah away from our heels, calluses at the site of a removed branch are good. They prevent disease organisms from infesting the wood deep within a tree. Too often, though, the branch bark ridge is pruned away along with the rest of the branch. The pruning cut is made flush against the tree trunk, and it’s not just a flesh wound, or, in this case, I guess, a flush wound. Without the branch bark ridge, callus tissue can’t form.

And that’s where the fungus comes in. Like, literally where it gets into the tree.

Fungi are fascinately deceptive organisms. It’s easy to believe that a mushroom is the main part of a multicellular fungus, because that’s the part that we see. More importantly, it’s the part that we eat (assuming the shroom isn’t toxic), and sometimes, we just need to know enough to know what’s going to taste good on a pizza without killing us. It’s all about priorities.

A mushroom is only a reproductive structure, though, a part that pops up when the fungus is ready to release its spores into the wind and go forth and multiply across the land, even if “the land” is just the several-yard radius of the front lawn. What a fungus really is is a collection of filaments called hyphae. Each hypha is a group of cells that looks like a thread and that grows snaking its way through dark spaces, often joining with other hyphae in a big clump to form a mass that’s called a mycelium. Patches of dirt and soil make excellent places for fungal hyphae to develop into more massive organisms.

So do the insides of trees.

If an external wound in a tree isn’t sealed with callus tissue, it leaves the tree’s sensitive inner tissues, the channels that carry water and nutrients from the root to the stem, exposed to creatures that want to devour them. Once fungi make their way into an open wound, it isn’t hard for them to reach their hyphae all the way through the tree’s otherwise hidden nooks and crannies. It’s everything that makes you squeamish when you read in some kind of sci-fi story about a tentacle monster trying to stick its tendrils into any crevasse it can find on the hero’s body, except that it happens on a much smaller scale inside of wood, and it happens every day around the world. Oh, and, in a way, it’s even more violent.

Fungi are heterotrophs, meaning that they have to consume external matter to get the nutrients they need to live. Humans are, too, so we have something in common. However, human beings politely digest their foods inside their stomachs, away from the view of one another. Fungi? Not so much. They engage in what’s called extracellular digestion: they secrete enzymes from their bodies, decompose the substance of a tree outside of themselves, and then absorb the broken-down nutrients through their cells. Imagine if you ate your grilled cheese by slapping your hand down onto it, secreting some acidic chemicals from your hand that decomposed the sandwich into mush, and then absorbing good nutrients from the mush through your skin.

I can’t lie. Part of me finds that a little disturbing; the other part of me is impressed. Would you believe, though, that some plants actually need fungi to do this in order to survive?

The fungi that consume a tree through its innermost heartwood are considered parasitic, meaning that they benefit while the trees that host them suffer. Fungi that eat dead matter are called saprophytic. Many fungi, though, benefit the plants they’re living on as well as themselves when they invade. These fungi are called mutualists, and they most often make their way through a plant’s roots.

Orchids in the wild serve as a widely known example of mutualism. When fungal hyphae invade a plant’s roots, they create a hybrid structure called mycorrhizae. As botanist Hans Burgeff discovered in the early 1900s, when certain fungi attach themselves to orchid roots, they carry nutrients from deep within soil up to the orchid and share them via the channels created when the fungi invaded. The orchids get an extra source of sustenance that their roots didn’t reach; the fungi get a host that provides them with sugars made during photosynthesis. When mycorrhizae are involved, everyone wins!

Hardwood trees like elm and ash trees can benefit from mutualistic fungi, too. A biologist named Stewart Millerhas shown that these trees are excellent hosts for the morel mushroom, a tasty fungus that, like many culinary delicacies, can be described as “freakin’ weird-looking.” The tree gets deep-soil nutrients; the fungus gets to suck on some tree sap. Of course, the fungus doesn’t actually produce those delicious mushrooms until the tree starts dying a little, sending the fungus into a Jor-El-like “last-ditch attempt at survival” mode, so there’s that downside.

As destructive as the activities of lignicolous, or wood-dwelling, fungi may seem it’s important to remember that fungi play crucial in outdoor habitats. They break down the dead tree stumps that otherwise would pile up on the forest floor, and they make the nutrients from dead matter available for plants to use so that they can grow. Even when fungi hollow out a tree trunk, they create holes that creatures like squirrels and owls use as homes. (Fun fact: standing dead trees that animals occupyare known as snags.)

Basically, thanks to fungi, a dying tree still gets to participate in life, and without all the hassle of returning as a zombie-tree or as some kind of cannibalistic tree-monster as seen in the drawing above. That seems like a pretty good arrangement to me.

For a list of some common wood rot fungi, click on this link. Have your own experiences with tree snags or with lovely lignicolous fungi? Leave a reply and let us know! (Be sure you’ve clicked on the individual post link to see the reply box below!)